• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.228-229
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• 2006

본 연구에서는 PCB에 적용하기 위한 폴리머 타입 후막저항의 하나로서, 포토공정으로 저항 패턴의 형성이 가능한 페이스트를 제조하였다. 기존의 폴리머 후막저항은 스크린 인쇄를 패터닝의 주요 방법으로 하고 있어 패턴의 정밀성이 떨어지는 단점이 있었다. 이를 개선하여 고정밀 저항 패턴의 형성이 가능하도록 Photoimageable Resin을 저항 페이스트의 개발에 도입하였다. Acrylated oligomer 및 monomer, 그리고 Novolac Epoxy를 주 기지상 재료로서 사용하였으며, acrylate와 epoxy의 함량비에 따른 저항 페이스트의 현상성 및 시트저항을 평가하였다. 전도성 Filler 재료로 카본블랙을 이용하였는데, 그 물리적 특성차와 함량이 저항 페이스트의 현상성과 저항값에 미치는 영향을 평가하였다. 실험결과 Acrylate와 epoxy의 비가 2.5:1일 때 현상성이 가장 양호하였으며, 이 조성에 XC72R 카본블랙을 2g 첨가하였을 때 시트저항의 평균값은 약 $6\;k{\Omega}\{\square}$였다.

• Applied Chemistry for Engineering
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• v.23 no.2
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• pp.157-163
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• 2012

Using six kinds of epoxy acrylates and a conductive carbon black, photosensitive resistor pastes were fabricated and then their developability in alkaline aqueous solution and the resistance values after thermal curing were evaluated. In order to impart the photocurability by UV exposure and the developability on alkaline solution, epoxy acrylate oligomers with carboxyl group, acrylate monomers, a photoinitiator and so forth were used. In addition, an organic peroxide was added into the paste to get a thermally curable composition. As a result, some of the pastes were not developed depending on the kinds of oligomers and, in the developed pastes, the measured resistance showed the different values depending on their compositions, even though they contain the same amount of carbon black. Finally, the optimum oligomer was selected and then, by adjusting the amount of carbon black, the kind of monomer and the curing temperature, the photosensitive resistor paste composition which showed the sheet resistance of about 0.5 $k{\Omega}/sq.$ could be obtained.

• Polymer(Korea)
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• v.28 no.6
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• pp.531-537
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• 2004

Various half-ester acrylates were prepared from anhydrides and 2-hydroxyethyl acrylate. Photocurable epoxy modified acrylates were prepared from synthesized half-ester acrylate and neopentylglycol diglycidylether. Physical properties such as hardness, yellowing, tensile strength and elongation were tested and compared as the structure of oligomer in cured-film differs. It was found that viscosity of neopentylglycol diglycidylether-hexahydrophthalic anhydride (NP-HA) was highest. Hardness and tensile strength of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride were better than those of other photocrosslinted epoxy acrylates. And 5% weight loss temperature of photocrosslinked neopentylglycol diglycidylether-hexahydrophthalic anhydride was higher than those of other photocrosslinked epoxy acrylates. Value of yellow index of photocrosslinked neopentylglycol diglycidyl ether-succinic anhydride (NP-SA) was lower than the other products.

• Journal of the Korean Wood Science and Technology
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• v.36 no.6
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• pp.121-129
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• 2008

Environmental friendly UV-curable coatings, having excellent hardness, gloss, mar and chemical resistance, are commonly used for the wooden flooring coatings. Especially epoxy acrylate oligomers are chosen for the wooden flooring coatings, due to their thermal stability and fast curing. In this study, we investigated the effect of the acrylate functionality on the thermal stability and surface hardness. The thermal degradations of monomers, oligomer, photoinitiator and formulated coatings with different acrylate functionality were measured using a thermogravimetric analysis (TGA). And the surface hardness was also measured with a pendulum hardness tester to compare relationship between the thermal stability and the physical property. The cured coatings became thermally stable by crosslinking during UV-curing. Both the thermal stability and surface hardness of cured coatings were improved with increasing acrylate functionality.

• Textile Coloration and Finishing
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• v.29 no.1
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• pp.37-44
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• 2017

An issue of major concern in the utilization of laminated composites based epoxy resin is associated with the occurrence of delaminations or interlaminar cracks, which may be related to manufacturing defects or are induced in service by low-velocity impacts. A strong interfacial filament/brittle epoxy resin bonding can, however, be combined with the high fracture toughness of weak interfacial bonding, when the filaments are arranged to have alternate sections of shear stress. To improve this drawback of the epoxy resin, UV-thermal dual curable resin were developed. This paper presents UV-thermal dual curable resin which were prepared using epoxy acrylate oligomer, photoinitiators, a thermal-curing agent and thermoset epoxy resin. The UV curing behaviors and characteristics of UV-thermal dual curable epoxy resin were investigated using Photo-DSC, DMA and FTIR-ATR spectroscopy. The mechanical properties of UV-thermal dual curable epoxy resin impregnated CF prepreg by UV curable resin content were measured with Tensile, Flextural, ILSS and Sharpy impact test. The obtained results showed that UV curable resin content improves the epoxy toughness.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.421-421
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• 2008

Generally, the polymer thick-film resistors for embedded organic or hybrid substrate are patterned by screen printing so that the accuracy of resistor pattern is not good and the tolerance of resistance is too high(${\pm}$20~30%). To reform these demerits, a method using Fodel$^{(R)}$ technology, which is the patterning method using a photosensitive resin to be developable by aqueous alkali-solution as a base polymer for thick-film pastes, was recently incorporated for the patterning of thermosetting thick-film resistor paste. Alkali-solution developable photosensitive resin system has a merit that the precise patterns can be obtained by UV exposure and aqueous development, so the essential point is to get the composition similar to PSR(photo solder resist) used for PCB process. In present research, we made the photopatternable resistor pastes using 8 kinds of epoxy acrylates and a conductive carbonblack (CDX-7055 Ultra), evaluated their developing performance, and then measured the resistance after final curing. To become developable by alkali-solution, epoxy acrylate oligomers with carboxyl group were prepared. Test coupons were fabricated by patterning copper foil on FR-4 CCL board, plating Ni/Au on the patterned copper electrode, applying the resistor paste on the board, exposing the applied paste to UV through Cr mask with resistor patterns, developing the exposed paste with aqueous alkali-solution (1wt% $Na_2CO_3$), drying the patterned paste at $80^{\circ}C$ oven, and then curing it at $200^{\circ}C$ during 1 hour. As a result, some test compositions couldn't be developed according to the kind of oligomer and, in the developed compositions, the measured resistance showed different results depending on the paste compositions though they had the same amount of carbonblack.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.499-506
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• 2013

As the usuage of tempered glass for touch panel increased rapidly with the development of industry, the amount of UV curable coating solution used to protect glass surfaces during a tempered glass manufacturing process increased as well. The UV curable coating has advantages compared to thermal curing such as shortened curing time and non-solvent. Appropriated polymer and monomer were used as an acid polymer to grant an alkali peeling ability. The monomers were 2-hydroxyl methylacrylate, 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate which have acryl groups of 1, 2, and 6, respectively. The combination of three different types of photoinhibitors were used and bisphenol A epoxy diacrylate was used as an oligomer. In this study, experiments were carried out by controlling the amount of photoinitiator, oligomer, and additive while maintaining the constant content of the acid polymer and the acrylic monomer. The changes in physical properties according to the additive content were investigated. It was found that the combination of photoinitiators was necessary to achieve the hardness above 4H and it was possible to control the delamination type of the coating film from a sheet to pieces by the addition of TPO as an initiator. The increase in oligomer contents increased the hardness and adhesiveness alongside dissection time. Talc content of 20 wt% showed the best results.

• Journal of Adhesion and Interface
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• v.15 no.3
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• pp.116-122
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• 2014

This work deals with the effects of different oligomers, monomers, photoinitiators, and steel plates on the variation of gloss for UV coated steel plates at $20^{\circ}$ and $60^{\circ}$ (ASTM D523). The gloss value was more significantly varied with $20^{\circ}$ angle as compared with $60^{\circ}$. No substantial change in gloss was observed for the type of single oligomer; however, the gloss varied with the mixing ratios of oligomers, type and mixing ratio of monomers, type and concentration of photoinitiator, and type of steel plate. The maximum gloss value was observed when the mixing ratio of polyurethane acrylate (UA) to epoxy acrylate (EA) was 70 : 30, the mixing ratio of trimethylolpropantriacrylate (TMPTA) to tetrahydrofurfurylacrylate (THFA) was 5 : 5, the content of the mixed oligomer (UA : EA = 70 : 30) was 90 wt%, respectively. Darocur MBF of liquid type showed better gloss property than the solid type of Irgacure 184, and the gloss was decreased as the concentration of Darocur MBF increased from 1 to 4 wt%. Regarding the type of steel plate, GI steel plate showed better gloss property as compared with EG and primer-coated steel plates. The maximum gloss values of 95 GU and 120 GU, respectively, at $20^{\circ}$ and $60^{\circ}$ angles throughout the parametric study in the absence of leveling agents enhancing the gloss.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.260-268
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• 2017

Purpose: Manufacturing with AM (Additive manufacturing) technique has many advantages; but, due to insufficient study in the area, it is not being widely used in the general clinic. In this study, differences of flexural strength among various materials of 3 unit fixed dental prosthesis were analyzed. Materials and Methods: A metal jig for specimens that had a 3-unit-fixed dental prosthesis figure were fabricated. The jigs were made appropriately to the specifications of the specimens. Three different kinds of materials of specimens which were NC (mathacrylic esther based), DP-1 (Bisphenol A epoxy acrylate type oligomer based), and DT-1 (urethane acrylate based) were printed with DLP machine. Five specimens for each kind of material were printed with an angle of $30^{\circ}$ from the horizontal surface. The specimens were placed on the jig and the flexural strength was measured and recorded using Universal testing machine. The recorded data was analyzed in SPSS using One-way ANOVA and Tukey HSD to determine the significance of the differences of flexural strength among the groups. Results: The flexural strengths of each group were the followings: NC, $1119{\pm}305$ N; DP-1, $619{\pm}150$ N; DT-1, $413{\pm}65N$. Using One-way ANOVA and Tukey Honestly Significant Difference test, significant difference was found between NC and the other groups (P < 0.05), but there was no significant difference between DP-1 and DT-1 (P > 0.05). Conclusion: Higher flexural strength was shown in 3-unit-fixed dental prosthesis that were 3D printed using a DLP machine with NC material.